Bacterial cell culture processes have been developed for the growth of single cell bacteria, yeast and molds which can be characterized as encased with a tough cell wall. Mammalian cell culture, however, is much more complex because such cells are more delicate and have a more complex nutrient requirement for development. Large scale culture of bacterial type cells is highly developed and such culture techniques are less demanding and are not as difficult to cultivate as mammalian cells. Bacterial cells can be grown in large volumes of liquid medium and can be vigorously agitated without any significant damage. Mammalian cells, on the other hand, cannot withstand excessive turbulent action without damage to the cells and must be provided with a complex nutrient medium to support growth.
In addition, some mammalian cells have a special requirement and must attach themselves to some surface in order to duplicate. Recent technology has been established to grow mammalian cells in horizontally rotating bio-reactors where forced oxygenation is over a sufficient surface area to successfully grow mammalian cells on a large scale. Such devices are disclosed in U.S. Pat. No. 5,026,650, entitled "Horizontally Rotated Cell Culture System with a Coaxial Tubular Oxygenator", and U.S. Pat. No. 5,153,131, entitled "High Aspect Ratio Vessel and Method of Use". These systems function admirably but they are self-contained units and do not adapt for use with existing laboratory equipment and require specific rotational equipment and air pumps.